Field of the Invention
The present disclosure relates to a zoom lens system and an image capturing apparatus including the same, and is suitable for, for example, a television camera for broadcasting, a video camera, a digital still camera, a monitoring camera, a film camera.
Description of Related Art
In recent years, in image capturing apparatuses, such as television cameras, silver halide film cameras, digital cameras, and video cameras, there is a demand for a zoom lens system that has a wide view angle and a high zoom ratio, and, moreover, with a high optical performance.
For example, Japanese Patent Laid-Open No. 2001-183584 discloses a four-unit zoom lens system that is suitable for television cameras and that includes, from the object side to the image side, a positive first lens unit, a second lens unit having a negative refractive power that moves during zooming, a third lens unit having a positive refractive power, and a fourth lens unit that does not move for zooming. Furthermore, a segmental lens unit on the most image side of the first optical unit performs focusing while a segmental lens unit on the object side of the first optical unit is fixed during focusing.
The above Japanese Patent Laid-Open No. 2001-183584 discloses a zoom lens system that has a zoom ratio of about 65 times and an angle of view for shooting of about 60° at a wide angle end, and that achieves wide angle, high magnification, and high performance through, for example, selection of glass materials and configuration of the lenses in an appropriate manner.
In the zoom lens system disclosed in Japanese Patent Laid-Open No. 2001-183584, variation in axial chromatic aberration during zooming, variation in axial chromatic aberration due to change in object distance, and change in the performance around the telescopic end tend to increase with increase in magnification. Therefore, further improvements in the zoom lens system remain necessary.